Flotation of nonmetallic minerals



Patented Nov. 3, 19.52

UNITED STATES PATENT OFFICE 2,300,821 p nors'rron or nomim'ramc MINERALS assignors to American Cyanamid New York, N. Y., a corporation of Maine Application July 23, 1940, Serial No. 346,986

No Drawing.

C mpa y,

7 Claims. (Cl. 209-166) The present invention relates to improved flotation promoters for non-metallic minerals and more specifically relates to a method of improving the promoting power of the promoters ordinarily employed in concentrating non-metalliferous ore values by froth flotation.

It is well known in the art that the values of non-metalliferous ores can be concentrated or recovered by froth flotation processes in which fatty acid substances are employed as promoters. Among the more important promoters used heretofore are the free fatty acids themselves such as oleic acid, flsh oil fatty acids, talloel, fatty acid soaps, and the like. In carrying out the actual froth flotation operation these various promoters may be mixed with an alkali such as caustic soda along. with a water-immiscible oil such as fuel oil and may or may not also contain a frother such as pine oil or kerosene. One of the more important fields in which such reagent mixtures are employed is in the recovery of the values from phosphate ore materials by froth flotation. While such phosphate recovery processes have been employed successfully on a commercial basis, they are not entirely satisfactory in that it is difllcult to obtain a phosphate concentrate having a low I percentage of insoluble material. The value of the phosphate concentrate is very largely determined by the amount of insoluble material which is present and it is therefore very desirable that a phosphate concentrating process be developed in general to the treatment of such-non-metalliferous ores, it has been found to be particularly efllcient in the treatment of phosphate ores and cement rock. 4

In connection with the recovery of values from phosphate ores, we have found that we can reduce the percentage of insoluble in the concentrate on the average of about 1 to 2% when comparedto the ordinary fatty acid flotation process, while at the same time the percentage recovery is also increased. In obtaining these improved results, the reagent cost is increased only about $.01 per ton of phosphate concentrate and hence the present invention results in a very economical saving in concentration of phosphate ores. The higher grade concentrates will also bring a better price as a 1% increase in grade is equivalent'to about $.15 increase in value per ton of concenadaptable to the present process. In this conwhich would result in the production of concen' trates with a lower insoluble content.

In accordance withthe present invention, it

has been discovered that the promoting power of fatty acid type Promoters employed in concentrating non-metalliferous materials by froth flotation can be very greatly increased by diluting the flotation reagent with about 20% or less of a water-soluble ketone, water-soluble hydroxy ketones, or mixtures of such ketones with aliphatic alcohols.- The exact reason why the promoting power of the non-metallic flotation promoters is increased by diluting with a small amount of the ketone or ketone-alcohol mixture has .not been definitely determined,-and we do not desire therefore to limit the present invention to any theory or explanation as to why the promoting power is increased.

The process and reagent mixtures of this invention can be utilized for recovering the values by froth flotation from any of the non-metalliferous ores such as phosphate rock, limestone, fluorspar, manganese minerals, calcite, cement rock,

and the like. While the present invention relates 65 prised of the above ketones with aliphatic alco-' nection we may mix the fatty acid promoter diluted with the ketone or ketone-alcohol mixture. with'an equal quantity of fuel oil and then add this /50 mixture to the flotation feed or pulp containing the correct quantity of caustic and then condition for a short time prior to the froth flotation. The improved reagent mixture is also adaptable for processes in which a rougher concentrate is flrst produced and this rougher concentrate returned to the flotation cell and a cleaner concentrate produced, either with or without the addition of further quantities of the reagent mixture.

It is an advantage of the present invention that the promoting power of the fatty acid type -toin, acetol, acetonyl acetone, valeric lactone,

methyl ethyl ketone, diethyl ketone, and the like. These fatty acid promoters may likewise be diluted with about 20% or less of a mixture'comof the fatty acid-ketone mixture.

hols in varying proportions, that is to say, they may be mixed in equal quantities or mixtures may be employed having a larger proportion, of the ketone as well as mixtures having a larger proportion of alcohol. Among the aliphatic alcohols that have been found to be useful are those such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, octyl; the polyhydroxy alcohols such as glycol, diethylene glycol, or polyethylene glycols, and the various ether alcohols such as mono-methyl ether of diethylene glycol, mono-- ethyl ether of diethylene glycol, mono-butyl ether of diethylene glycol, and the like.

In using our improved promoters inconnection with the recovery of values from phosphate ores by froth flotation, the process may be practiced as follows:

For example, a Florida pebble phosphate flotation feed consisting mainly of tricalcium phosphate and silica, and in which'the particle size is preferably -28 mesh material, is diluted to a pulp density of about 72% solids. This pulp is then conditioned with the necessary reagents which may comprise from .5 to 1.5 lbs. per ton of feed of a promoter comprising a fatty acid dilu'ted with 20% acetone, from 2 to 4 lbs. of fuel oil per ton of feed, and from .5 to 1 lb. of caustic soda per ton of feed. After this conditioning treatment the pulp is transferred to a suitable flotation cell such as the Fagergren flotation machine and diluted to about 20-22% solids with water. This diluted pulp is then subjected to agitation and aeration to produce a rougher concentrate. The rougher concentrate-is returned to the flotation cell. without additional reagents and a cleaner concentrate obtained. The results obtained by the use of the reagent mixture described above are superior to results obtained when compared to the same process but in which fatty acids alone are used as a promoter instead The percentage B. P. L.- in the cleaner concentrate ranges from l-2.5% higher andat the same time the percentage insoluble in the cleaner concentrate is from .5-l.5% less. In the above described process similar results are obtained when the promoter employed is talloel plus 20% acetone, talloel plus acetone, talloel plus 20% (acetone-50%, ethyl alcohol-50%), or such mixtures when fish oil fatty acid is used instead process may be carried out as follows:

The cement rock in the form of a slurry is diluted to about 20-22% solids with water and placed in a suitable flotation cell. The reagent -mixture is then added, which may comprise a fatty acid such as oleic acid diluted with 20% acetone in the proportion of from .2-.'! lbs. per ton of ore.

The reagents are conditioned with the pulp'for a short time and then subjected to oil fatty acid diluted with 10% acetone as a promoter, we have found that the recovery of calcium carbonate is about 1 or 2% higher than the same process when flsh oil fatty acid alone is used as a promoter.

We claim:

1. In the recovery of phosphate ore values by froth flotation processes the method which comprises carrying out the flotation in the presence of a talloel phosphate ore promoter diluted with from about 10% to not more than 20% .of an aliphatic water-soluble ketone.

2. In the recovery of phosphate ore values by froth flotation processes the method which comprises carrying out the flotltion in the presence of a talloel phosphate ore promoter diluted with from about 10% to not more than 20% of acetone.'

3. In the recovery of values from cement rock by froth flotation the process which comprises carrying out the flotation in the presence of a flsh oil fatty acid diluted with from about 10 to not more than 20% of an aliphatic watersolubie ketone as the promoter.

4. In the recovery of values from cement rock. by froth flotation the process which comprises carrying out the flotation in the presence of 'a' flsh oil fatty acid diluted with from about 10% to not more than 20% of acetone as the flotation promoter.

5. The improvement in the recovery of nonmetallic ore values by froth flotation processes which comprises carrying out the flotation in the presence of a non-metallic .ore promoter of the group consisting of higher fatty acids and higher fatty acid soaps diluted with at least one of the substances included in the group consisting of aliphatic water-soluble ketones and mixtures of aliphatic water-soluble ketones with aliphatic alcohols, the total amount of said diluent,

being from about 10% to not more than 20% of the amount of promoter present.

6. In the recovery of phosphate ore values by froth flotation processes, the method which comprises carrying out the flotation in the presence of a fatty acid phosphate promoter of thegroup consisting of higher fatty acids and higher fatty acid soaps dilutedwith at least one of the substances included'in the group consisting of aliphatic water-soluble ketones and mixtures of aliphatic water-soluble ketones' with aliphatic alcohols, the total amount of said diluent being from about 10% to not more than 20% of the amount of promoter present.

7. In the recovery of cement rock values by froth flotation processes, the method which coinprises carrying out the flotation in the presence of a fatty acid calcite promoter of the group consisting of higher fatty acids and higher fatty acid soaps diluted with at least one-of the substances included in the group consisting ofall phatic water-soluble ketones and mixtures of all-* phatic water-soluble ketones-with aliphatic alcohols, the total amount of said diluent being from about 10% to not more than 20% of the amount of promoter present. l

LUDWIG JACOB CHRISTMANN. STEPHEN EDWARD ERICKSON'. 

